Many different methods of delivering playable media to users have been suggested. Perhaps the most ubiquitous among such methods, is the DVD, and its follow on generation “Blue Ray”. These disks include media thereon in an encrypted form.
In the DVD, the encryption key is also readable from the media so that a player can play the media to the user. Other more sophisticated forms of encryption and decryption have been used with new media techniques such as blue ray. Some, for example, hard-code a decryption key into the players.
Each of these, however, have their own host of disadvantages, and allow a sufficiently dedicated hacker to find the media decryption key and use it to play back the decrypted media. DVD-decryption programs can be downloaded, for example. The blue-ray decryption keys are often posted on the internet. All of these allow obtaining a surreptitious digital copy of the media being played.
Also, video recording devices, such as digital video recorders, may store media.